Carbon dioxide solid capture material

Abstract

In order to provide a durable carbon dioxide solid capture material that can be used over a long period of time and can be used repeatedly for gases containing water, in particular, this carbon dioxide solid capture material contains iron, sodium, and crystalline carbon, and more specifically, contains sodium ferrite, crystalline carbon, and at least one binder selected from among amorphous carbon, polyamide-imides, polyesters, epoxy resins, polyurethanes, and acrylic resins.

Description

Solid carbon dioxide capture material

[0001] The present invention relates to a solid recovery material for immobilizing carbon dioxide and a method for producing the same, and in particular to a solid recovery material containing sodium ferrite.

[0002] Research into the capture, storage, and utilization of carbon dioxide has been ongoing for some time now in order to reduce the amount of carbon dioxide released into the atmosphere. Large-scale sources of carbon dioxide include thermal power plants that use coal, heavy oil, or natural gas as fuel, boilers in manufacturing plants, and kilns in cement plants. Other sources include blast furnaces in steel mills that reduce iron oxide with coke, and transportation vehicles such as automobiles, ships, and airplanes that use gasoline, heavy oil, or light oil as fuel.

[0003] Patent Document 1 discloses that a solid carbon dioxide recovery material containing sodium ferrite can be obtained by adding an organic or inorganic binder to the material, and that a solid recovery material containing a high concentration of sodium ferrite can be obtained. Patent Document 1 also discloses polystyrene, polyethylene, and the like as organic binders, and Na, Li, K, and the like as inorganic binders.

[0004] International Publication No. 2022 / 259929

[0005] For a solid carbon dioxide capture material to be put to practical use, not only performance such as the amount of carbon dioxide captured is required, but also durability.

[0006] An object of the present invention is to provide a solid carbon dioxide recovery material that can be used for a long period of time.

[0007] The present invention provides a solid carbon dioxide recovery material containing iron, sodium, and crystalline carbon. The crystalline carbon may be at least one material selected from graphite, carbon nanotubes, acetylene black, and calcine coke. The solid recovery material may further contain a binder. The binder may be at least one material selected from amorphous carbon, polyamideimide, polyester, epoxy resin, polyurethane, and acrylic resin. The binder may include a burned pitch. The total carbon content of the crystalline carbon and the binder may be 10 to 70 wt %. The solid recovery material may contain sodium ferrite. The composition ratio of Fe contained in the solid recovery material may be 5 to 50 wt %.

[0008] The solid carbon dioxide capture material according to the present invention has water resistance and strength, and is therefore durable enough to be used for a long period of time.

[0009] DETAILED DESCRIPTION OF THE INVENTION The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its uses.

[0010] A solid carbon dioxide capture material according to one embodiment of the present invention (hereinafter, sometimes simply referred to as "solid capture material") will be described.

[0011] The solid carbon dioxide capture material according to this embodiment contains iron (Fe), sodium (Na), and crystalline carbon.

[0012] The form of Fe contained in the solid recovery material is not particularly limited. In other words, Fe may be a simple substance or a compound, and its phase (α, β, γ, etc.) is not limited. When the solid recovery material contains Fe as a compound, the components other than Fe in the compound are not limited. Furthermore, the solid recovery material may contain Fe in one or more forms. For example, the form of Fe may be α-Fe, FeO, or / and Fe ３ O ４ Examples include:

[0013] The composition ratio of Fe contained in the solid recovered material is preferably 5 to 50 wt %, more preferably 8 to 40 wt %, and even more preferably 11 to 30 wt %. If the composition ratio is within this range, the strength is excellent.

[0014] The form of Na contained in the solid recovery material is not particularly limited, and may contain one type or two or more types. For example, Na ２ CO ３ (H ２ O) or / and Na ２ CO ３ Examples include:

[0015] The composition ratio of Na contained in the solid recovery material is preferably 1 to 20 wt %, more preferably 1.5 to 15 wt %, and even more preferably 2 to 10 wt %. If this composition ratio is within this range, a good carbon dioxide recovery rate will be achieved.

[0016] The Fe and Na contained in the solid recovered material are converted into sodium ferrite (NaFeO ２ In other words, the solid recovery material may contain sodium ferrite. The form of sodium ferrite is not particularly limited, and one or more types may be included. For example, the form of sodium ferrite may be α-NaFeO ２ or / and β-NaFeO ２ Examples include:

[0017] In addition, the reaction formula between sodium ferrite and carbon dioxide is NaFeO when the gas does not contain water vapor. ２ +1 / 2CO ２ →1 / 2Na ２ CO ３ +1 / 2Fe ２ O ３ When water vapor is included, NaFeO ２ +CO ２ +1 / 2H ２ O → NaHCO ３ +1 / 2Fe ２ O ３Furthermore, by placing the solid recovery material after the reaction with carbon dioxide under a predetermined temperature condition in an atmosphere that does not contain carbon dioxide, the carbon dioxide can be desorbed. In this way, the solid recovery material can repeatedly adsorb, fix, and desorb carbon dioxide.

[0018] When the solid recovery material contains sodium ferrite, the sodium ferrite preferably has a molar ratio of Na / Fe of 0.7 to 1.3. This molar ratio range allows the solid recovery material to contain a large amount of sodium ferrite crystalline phase, resulting in good carbon dioxide capture and recovery performance.

[0019] When the solid collection material contains sodium ferrite, the sodium ferrite powder preferably has a pH value of 8 to 14. When the powder has a pH value of 8 to 14, the solid carbon dioxide collection material according to this embodiment becomes basic and easily captures carbon dioxide, which is weakly acidic.

[0020] When the solid recovery material contains sodium ferrite, the axial ratio of the average major axis diameter to the average minor axis diameter of the primary particles of sodium ferrite (average major axis diameter / average minor axis diameter) is preferably 1 to 2. When the axial ratio is within the above range, the primary particles of sodium ferrite are less likely to aggregate with each other and can have high dispersibility. The axial ratio of the primary particles of sodium ferrite is more preferably 1.1 to 1.9.

[0021] The crystalline carbon contained in the solid recovery material is preferably at least one substance selected from graphite, carbon nanotubes, acetylene black, and calcine coke, and two or more may be used in combination. Crystalline carbon functions as an aggregate that provides strength to the solid recovery material and maintains its shape. Furthermore, solid recovery materials containing crystalline carbon are water-resistant, and are therefore preferably used for treating gases containing water. Furthermore, crystalline carbon can provide the solid recovery material with a structure that allows carbon dioxide to come into contact with Fe and Na (including compounds such as sodium ferrite) contained in the solid recovery material, specifically, fine voids.

[0022] The solid recovered material preferably contains a binder. The binder maintains the shape of the solid recovered material by binding together elements constituting the solid recovered material, such as Fe, Na, and crystalline carbon. The solid recovered material preferably contains at least one of amorphous carbon and a polymer as a binder, and may contain one or more types of binders. Examples of polymers include polyamideimide, polyester, epoxy resin, polyurethane, and acrylic resin. Examples of amorphous carbon include burned pitch. Pitch is a by-product of petroleum or coal tar.

[0023] By containing crystalline carbon and the above-mentioned binder, the solid recovery material can maintain its structure even when used repeatedly over a long period of time. Generally, the solid recovery material is filled in a container when in use. A structure having a container and a plurality of solid recovery materials filled in this container is called an adsorption tower. In the adsorption tower, the gas to be treated passes through the gaps between the solid recovery materials. If the solid recovery material collapses, the gas flow path becomes narrow or collapses, resulting in a large pressure loss.

[0024] When the binder is a polymer, its weight-average molecular weight is preferably 1,000 to 100,000. If the weight-average molecular weight is less than 1,000, the molded body may be too soft, resulting in reduced strength. If the weight-average molecular weight exceeds 100,000, the organic binder may be too hard, making it difficult to form a molded body.

[0025] In the solid recovered material, the ratio of the total carbon components of the crystalline carbon and the binder is preferably 10 to 70% by weight, more preferably 15 to 65% by weight, and even more preferably 20 to 60% by weight. By keeping this composition ratio within the above range, high strength and water resistance can be obtained.

[0026] The solid recovery material preferably contains iron (Fe), sodium (Na) and crystalline carbon, with the remainder being oxygen.

[0027] The solid recovery material preferably has a particle size of 1 mm to 10 mm. The particle size is the average value of the major axis and minor axis of the solid recovery material. If the particle size is 1 mm or more, gaps can be secured in the adsorption tower between the solid recovery materials through which the gas to be treated can pass, thereby minimizing pressure loss to a practical level. If the particle size is 10 mm or less, the contact rate between Fe and carbon dioxide increases, allowing carbon dioxide to be recovered efficiently. It is more preferable that the particle size of the solid recovery material is 2 mm to 8 mm.

[0028] The shape of the solid recovery material is not particularly limited, but is preferably cylindrical, spindle-shaped, rectangular, cuboid, cuboid, spherical, or the like.

[0029] The axial ratio of the solid recovery material, i.e., the value obtained by dividing the length of the long axis of the solid recovery material by the length of the short axis, is preferably 1 to 5. When the axial ratio is 1 or more, voids that serve as gas flow paths are easily formed between the solid recovery material. On the other hand, when the axial ratio is 5 or less, the void size becomes large enough to allow efficient contact between carbon dioxide and Fe and Na, and the voids can be uniformly distributed throughout the adsorption tower. The axial ratio is more preferably 1.5 to 4.

[0030] The strength of the solid recovery material is preferably 20 N or more, more preferably 60 N or more, and even more preferably 100 N or more. The solid recovery material located particularly at the lower part of the adsorption tower is subjected to pressure from the solid recovery material above. Furthermore, when the gas to be treated is passed through the adsorption tower, the solid recovery material is also subjected to pressure from the gas. When the strength is within the above range, the solid recovery material is less likely to pulverize, and the gas to be treated, such as exhaust gas, can more easily flow through the adsorption tower.

[0031] The porosity of the solid recovery material is preferably 20 to 80% by volume, more preferably 25 to 70% by volume, and even more preferably 30 to 65% by volume. When the porosity is within this range, the carbon dioxide contained in the gas to be treated easily comes into contact with the solid recovery material, allowing for efficient recovery of carbon dioxide.

[0032] The bulk density of the solid recovery material is preferably 0.4 g / cc or more, and more preferably 0.45 g / cc or more. When the bulk density is in this range, the packing property into the adsorption tower is improved. The upper limit of the bulk density is about 1 g / cc.

[0033] Next, an example of a method for producing the solid carbon dioxide recovery material will be described. The solid recovery material is not limited to the following method.

[0034] The method for producing the solid recovered material includes a kneading step of kneading a carbon dioxide absorbent containing Fe and Na with an aggregate containing crystalline carbon, and a molding step of molding the kneaded mixture.

[0035] The kneaded material preferably contains 20 to 140 parts by weight of aggregate per 100 parts by weight of the carbon dioxide absorbent.

[0036] In the kneading step, the Fe raw material and the Na raw material may be sodium ferrite as described above. Materials such as a binder may be further added to the above materials. The kneaded mixture preferably contains 0 to 50 parts by weight, and more preferably 10 to 40 parts by weight, of a binder per 100 parts by weight of the carbon dioxide absorbent. Liquids such as water and organic solvents may also be added. For kneading, kneading devices such as a double-arm kneader, a screw kneader, a Muller mill, a plow mixer, and a planetary mixer may be used.

[0037] In the molding step, techniques such as die cutting, extrusion (screw, roller, etc.), rolling, cutting, spheronization, etc. can be used alone or in combination. For example, the kneaded material may be extruded using an extruder and then cut to a predetermined length.

[0038] The method for producing the solid recovered material may further include a drying step of drying the formed product after forming.

[0039] Furthermore, the manufacturing method of solid recovered material may include a firing step in which the shaped product is fired. If a drying step is performed, the firing step may be performed after the drying step. The firing is preferably performed in a nitrogen atmosphere. In addition to normal firing, steam heating, microwave heating, ultrasonic heating, etc. may also be performed. The firing temperature and time are appropriately set so as to obtain a solid recovered material having the desired strength. Although the firing depends on the types of aggregate and binder, it is preferable to treat at a temperature of 100°C or higher and 1000°C or lower. For example, when pitch is used as the binder, it is preferable to fire at a temperature higher than the temperature at which the oil volatilizes, for example, 500°C or higher is preferable.

[0040] The method for producing the solid recovery material may further include a step of producing sodium ferrite, which may involve a solid-phase reaction between an iron oxide-containing material and a sodium-containing material. Specifically, the iron oxide-containing material and the sodium-containing material are mixed and ground, then calcined, and then appropriately ground to obtain sodium ferrite particle powder. Examples of the iron oxide-containing material include hematite, magnetite, maghemite, and / or goethite. Examples of the sodium-containing material include sodium nitrite, sodium hydroxide, sodium oxide, and / or sodium carbonate.

[0041] As described above, the solid recovery material can be applied to an adsorption tower. The adsorption tower includes a container and a plurality of solid recovery materials packed in the container. In the adsorption tower, the average particle size of the solid recovery material is preferably 1 mm to 10 mm. The average particle size can be calculated by measuring the major and minor axes of 80 particles and averaging the results.

[0042] The dimensions of the container and the amount of solid recovery material packed therein can be changed depending on the conditions of use and purpose of the adsorption tower.

[0043] The solid recovery material can selectively adsorb and fix carbon dioxide from a gas containing carbon dioxide. During adsorption, the gas to be treated is brought into contact with the solid recovery material. The temperature at this time is preferably about 20 to 80°C.

[0044] The solid recovery material with fixed carbon dioxide can be placed under temperature conditions of about 50°C to 200°C to desorb the carbon dioxide.

[0045] The solid recovery material after desorption can be used for further adsorption and fixation of carbon dioxide, and therefore the solid recovery material can be used repeatedly.

[0046] <Production of Solid Recycled Material> Examples 1 to 7 and Comparative Example 1: The aggregates, binders, and sodium ferrite (NaFeO ２ ) were weighed out to the weight ratio shown in Table 1 and mixed. The mixture was charged into a kneader, and 100 parts by weight of water was added and kneaded for 1 hour. After kneading, the mixture was molded into a diameter of 2 mm using an extrusion molding machine and cut into a length of 5 mm. After cutting, the mixture was dried at a drying temperature of 60°C for 12 hours and calcined at a temperature of 600°C for 3 hours using a nitrogen atmosphere furnace to obtain a solid recovered material.

[0047] Example 8: A solid recovered material was obtained in the same manner as in Example 1, except that the materials and weight ratios shown in Table 1 were mixed without adding water and the firing temperature was set to 200°C.

[0048] Comparative Example 2: A solid recovery material was obtained in the same manner as in Example 1, except that the materials and weight ratios were as shown in Table 1 and no firing was performed.

[0049] Comparative Example 3: A solid recovered material was obtained in the same manner as in Example 1, except that no aggregate was used and the materials and weight ratios were as shown in Table 1.

[0050]

[0051] <Analysis> (Crystallinity) The compounds contained in the aggregates and binders of the solid recovered materials of the above Examples and Comparative Examples are shown in Table 2. When the compound contained in the aggregates and binders is carbon (C), the state (crystalline / amorphous) is also shown in Table 2.

[0052] The solid recovered material was pulverized in a mortar and pulverized using a BRUKER D8 ADVANCE fully automated multipurpose X-ray diffractometer. The crystallite size of the (002) plane was determined using the Scherrer equation. The average interplanar spacing d(002) was also determined using the Bragg equation. Carbons with an average interplanar spacing d(002) of 3.35 to 3.6 Å or a crystallite size of 20 to 400 Å were considered to be crystalline carbon.

[0053] Furthermore, a separate sample of the binder was prepared by firing it under the same conditions as the solid recovered material, and since no crystalline peak was detected using the same equipment as described above, it was identified as amorphous carbon. After removing the Na and Fe components contained in the recovered material with hydrochloric acid, the sample was observed with a scanning electron microscope and found to contain carbon components other than crystalline carbon, indicating that the binder contained amorphous carbon.

[0054]

[0055] (Average particle size) The major and minor axes of 80 particles were measured using a vernier caliper. Each solid recovered material maintained the same dimensions as when it was molded. The average value of the measurement results was taken as the average particle size.

[0056] (Porosity) The porosity of the solid recovered material was measured by mercury intrusion porosimetry in accordance with JIS R1655.

[0057] (Bulk Density) The bulk density of the solid recovered material was measured in accordance with JIS Z2504.

[0058]

[0059] (Compound Composition of Solid Recovered Material) The solid recovered material was pulverized in a mortar, and the carbon dioxide absorbing components and aggregates were identified using a fully automatic multipurpose X-ray diffractometer D8 ADVANCE manufactured by BRUKER.

[0060] (Elemental composition ratio of solid recovered material) Pretreatment for elemental analysis and quantification excluding carbon and oxygen was carried out by pulverizing the solid recovered material in a mortar, adding 1 part by weight each of the solid recovered material and the molding agent, high-purity cellulose powder SpectoroBlend 44 μm powder (Chemplex Industries, Inc.), and mixing using a planetary mixer. Thereafter, the mixture was compacted into a powder molded product having a diameter of 10 mm and a thickness of 1 mm, and elemental analysis and quantification excluding carbon and oxygen were carried out using a Rigaku scanning X-ray fluorescence analyzer ZSX Primus II.

[0061] Carbon was quantified using a carbon / sulfur analyzer (EMIA-920V2; HORIBA Co., Ltd.), and oxygen was quantified using an oxygen / nitrogen / hydrogen analyzer (EMGA-930; HORIBA Co., Ltd.).

[0062]

[0063] <Performance Evaluation> (Water Resistance) 100 ml of pure water was poured into a 200 ml beaker, and 10 g of the solid collection material was submerged. After submersion, the material was left to stand at 30°C, and the change in shape of the solid collection material over time was visually observed. The water resistance was judged as pass if the time it took for the shape of the solid collection material to change after submersion was less than 5 hours, and pass if it took 5 hours or more. The solid collection materials of Examples 1 to 8 did not show any change in shape even when submerged in water for more than one month.

[0064] (Carbon dioxide recovery rate) To evaluate the carbon dioxide fixation and recovery performance of the solid recovery material, the carbon dioxide recovery rate was measured as follows. The solid recovery material was loaded to a height of 300 mm in a packed tower column (diameter 25 mm x height 500 mm) as an adsorption tower. The system was adjusted to 40°C and relative humidity 80 RH%, and a mixed gas of 10 vol% carbon dioxide and 90 vol% nitrogen was passed through the adsorption tower at GHSV 490 h. －１ The packed tower column was then heated to 150°C and carbon dioxide was desorbed from the solid recovery material over a period of 2 hours. The instantaneous concentration of the desorbed carbon dioxide was measured using an infrared gas monitor RI-557 (manufactured by Riken Keiki Co., Ltd.), and the amount of carbon dioxide recovered was calculated based on the measurement results. Furthermore, the carbon dioxide recovery rate (wt%) was calculated as the amount recovered per unit weight of the solid recovery material at the time of packing.

[0065] (Average crushing strength) The strength of the solid recovered material was measured using an Imada digital force gauge ZP-500N. Press pressure was applied to the long axis side of the cylindrical solid recovered material, and the strength at which the solid recovered material was crushed was taken as the crushing strength, expressed in units of Newtons (N). The average value of the crushing strength of 80 grains was taken as the average crushing strength. An average crushing strength of 100 N or more was rated as excellent, 20 to 100 N, good, and less than 20 N, unacceptable.

[0066]

[0067] The solid recovered materials obtained in Examples 1 to 7 contained Na, Fe, and crystalline carbon. ２ CO ３ (H ２ O), Na ２ CO ３ , α-NaFeO ２ , β‐NaFeO ２ , α-Fe, FeO, Fe ３ O ４ and the aggregates listed in Table 4. The solid recovered materials obtained in Examples 1 to 7 further contained amorphous carbon. Furthermore, even after carbon dioxide adsorption and desorption, the phases of the compounds contained in the solid recovered materials remained unchanged.

[0068] The solid recovered material obtained in Example 8 contained Na, Fe, and crystalline carbon. ２ CO ３ (H ２ O), Na ２ CO ３ , α-NaFeO ２ and CNTs. The solid recovery material obtained in Example 8 further contained a polymer resin. Furthermore, even after carbon dioxide adsorption and desorption, the phase of the compounds contained in the solid recovery material remained unchanged.

[0069] On the other hand, the solid recovered materials obtained in Comparative Examples 1 to 3 contained Na and Fe. Specifically, in Comparative Example 1, Na ２ CO ３ (H ２ O), α-NaFeO ２ , Fe ３ O４ and cordierite, and in Comparative Example 2, Na ２ CO ３ (H ２ O), Na ２ CO ３ , α-NaFeO ２ and cellulose, in Comparative Example 3, Na ２ CO ３ (H ２ O), Na ２ CO ３ , α-NaFeO ２ , β‐NaFeO ２、 α-Fe, FeO and Fe ３ O ４ It included:

[0070] However, since the solid recovered materials of Comparative Examples 1 to 3 did not contain crystalline carbon, they all failed the water resistance test. Furthermore, since the solid recovered material of Comparative Example 2 did not contain a binder, it also had poor average crushing strength.

[0071] As described above, the solid recovery material according to the present invention, which contains Na, Fe, and crystalline carbon, has high crushing strength and water resistance as well as the ability to recover carbon dioxide, and exhibits durability.

[0072] It is suitable as a solid carbon dioxide capture material. Its excellent durability allows repeated adsorption and desorption, making it industrially useful.

Claims

1. A solid carbon dioxide capture material containing iron, sodium and crystalline carbon.

2. The carbon dioxide solid recovery material according to claim 1, wherein the crystalline carbon is at least one material selected from the group consisting of graphite, carbon nanotubes, acetylene black and calcined coke.

3. The carbon dioxide solid recovery material according to claim 1 or 2, further comprising a binder.

4. The carbon dioxide solid recovery material according to claim 3, wherein the binder is at least one substance selected from the group consisting of amorphous carbon, polyamide-imide, polyester, epoxy resin, polyurethane and acrylic resin.

5. The carbon dioxide solid recovery material according to claim 3, wherein the binder contains a calcined product of pitch.

6. The carbon dioxide solid recovery material according to claim 4, wherein the total carbon content of the crystalline carbon and the binder is 10 to 70% by weight.

7. The solid carbon dioxide capture material according to claim 1, containing sodium ferrite.

8. A solid carbon dioxide capture material as described in claim 1, wherein the composition ratio of Fe contained in the solid capture material is 5 to 50% by weight.

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